This invention concerns projection television systems, and is largely directed to a system in which a rear projection screen, storable in the system cabinet, is elevatable for viewing.
A system of this type is described and fully claimed in referent copending application Ser. No. 228,434. A jack-in-the-box projection television receiver comprises a cabinet for enclosing the components of the receiver, and includes a lid hinged at the back of the cabinet. The receiver comprises a vertically arranged, elevatable rear projection screen selectively storable in the cabinet. Image source means provide for forming a television image. Stationary optical assembly means--the subject of the present application--provides for projecting an aerial image of a television image formed by the image source means along a folded optical path onto the screen when the optical path is erected, and the screen is located a predetermined image projection distance from the image source means. The receiver further includes means for elevating the screen from a first receiver-inoperable position wherein the screen is completely enclosed within the cabinet and the receiver is ultra-compact, to an elevated receiver-operable position wherein the screen is emerged from the cabinet. As a result, the optical path is extended to a length equal to the predetermined image projection distance whereby the projection image is coincident with the screen.
In U.S. Pat. No. 4,259,694, Reinhard discloses an invention that relates to a projection system for diapositive film strips. The projection system comprises an essentially cubic projection box, the front side of which comprises a ground glass plate as the screen. Inside, there is a projector and two reflecting mirrors arranged to project the projecting beam exiting from the projector onto the screen. The projector is disposed such that its optical axis passes through the optical center of an objective, forming an acute angle together with the optical axis of the objective. As a result, the principal ray of the projecting beam exiting from the projector is inclined toward that wall of the projection box at which the projector is located. The object of the invention appears to be to make possible a smaller depth of the projection box while providing a distortion-free image.
In U.S. Pat. No. 4,231,067 to Jewell et al., there is disclosed apparatus for supporting a television receiver housing and projecting an image from the face of the picture tube to a remote, reflective front projection screen. The apparatus includes a base providing an inclined support surface for the TV housing. A hood defining a closed path is included. At one end, the hood encircles the face of the TV picture tube, and at the opposite end, there is mounted a projection lens barrel frictionally engaged for unitary focusing movement. The apparatus is mounted on casters so that it can be moved about with respect to a free-standing viewing screen. The base is said to provide for quick mounting and removal of various sizes of TV sets.
In U.S. Pat. No. 3,943,282, Muntz discloses a projection television apparatus in which the projected image is reflected by a mirror contained in a pull-out drawer at the front of the cabinet. The reflected image is directed from the mirror to the front of a curved screen for display of the enlarged image. A television receiver is mounted on an inclined platform within the cabinet, with a cathode ray tube facing upwards. A mirror-and-lens system provides for directing the television image toward the mirror, and for enlarging the image.